1. Field of the Invention
This invention relates to high solids polycarboxylic acid soap compositions. More particularly, this invention relates to soap compositions having increased carboxyl content thereby having an increased soap solubility or solids content. These high solids soaps are the addition reaction of unsaturated, conjugated and unconjugated fatty acids and a maleyl compound.
2. The Prior Art
Two considerations which are important to fatty acid soap users are the saponifying agent used for the soap and the level of solids obtainable in maintaining a fluid soap. It seems in the majority of cases these two are related, for of the common saponifying agents, potassium and sodium the potassium soap is much more soluble. Therefore, when relatively high solids soaps are desired, the potassium soap is the standard for fatty acids. In most cases the sodium soap would serve just as well and be cheaper to produce, but since it is much less soluble and tends to crystallize, it is normally avoided. For example, using potassium soaps, the highest solids soaps that are still fluid at room temperature for several short and long chain fatty acid soaps are as follows:
Caprylic (C.sub.8) 45% Capric (C.sub.10) 40% Lauric (C.sub.12) 35% Coconut (Mixture of C.sub.10, C.sub.12, C.sub.14) 36% Tallow (C.sub.18) 17% Oleic (C.sub.18) 20% Dimer Acid (C.sub.36) 23%
As is obvious, the shorter chain soaps are more soluble and fluid than oleic-type fatty acid. The same trend is apparent with the sodium soaps of the various acids except the solubilities are lower.
The high solid soaps are made as adducts of the Diels-Alder reaction, using maleyl compounds as the dienophiles or by an addition reaction. The literature is therefore full of patents extolling the benefits and utility derived from the reaction of maleic anhydride with rosin, with rosin-fatty acid mixtures, fatty acids, and with many naturally occurring oils; however, none specifically teach increased solubility of soaps. In this regard, U.S. Pat. No. 3,639,650 to L. O. Cummings discloses adducts of unsaturated, unconjugated fatty oil, such as glyceride, and a maleyl compound reacted at a temperature between 300.degree.F. (149.degree.C.) and 350.degree.F. (177.degree.C.) in the presence of sulfur dioxide to reduce color for use in coatings. In The Journal of the American Oil Chemists' Society, (Volume 34, page 136 (1957)), Danzig et al. teach in an article entitled "Reactions of Conjugated Fatty Acids, V. Preparation and Properties of Diels-Alder Adducts and Their Esters from Trans, Trans-Conjugated Fatty Acids Derived From Soybean Oil" using iodine to convert linoleic portions of soybean fatty acids to the trans, trans conjugated form to prepare cyclic adducts.
It has been found that high solid polycarboxylic acid soaps may be made to substantially lessen the problem of gelation and extend crystallization of fatty acid soaps to before unknown high solids content without a conversion catalyst. It is therefore the general object of this invention to provide polycarboxylic acid soap compositions that are water soluble at high soap solids content. Another object is to provide a polycarboxylic acid soap using a variety of neutralizing agents and still retaining high water solubility. Still another object of this invention is to provide a process for making the high solids content polycarboxylic acid soaps from a variety of fatty acid and fatty oils. An even further object of this invention is to provide maleyl modified fatty acids and oils having a saponification number from 200 to 400 and lower viscosity at a given solids level than the unmodified fatty acid or oil.
Other objects, features and advantages of this invention will become apparent from the following detailed description.